Checks if element has class or not
SOURCE: http://stackoverflow.com/questions/1318076/jquery-hasattr-checking-to-see-if-there-is-an-attribute-on-an-element
by Annie Lagang
HTML
<h1 id="heading" class="sample">Welcome!</h1>
JavaScript
if ($("#heading").attr("class") && $("#heading").is('[class*="sample"]'))
alert('Look, this is showing because it\'s not undefined');
else
alert('This would be called if it were undefined or is there but empty');